1. Field of the Invention
The present invention relates to container fabrication equipment and more particularly to a method and apparatus for erecting paperboard containers from flat blanks therefore and sealing the bottom flaps thereof.
2. Prior Art
Paperboard cartons are commonly used by manufacturers to ship manufactured goods such as food products, machine parts and the like to distributors, retail outlets or ultimate consumers. Such paperboard cartons are frequently manufactured in the form of carton blanks which may be shipped flat for convenience and economy. Thus, it becomes necessary for the user of the carton to unfold or erect the blank and seal the bottom flaps prior to filling the carton with manufactured goods. A common form of carton comprises a single blank having four side panels joined together at opposite side edges of the panels and having four top panels and four bottom panels joined to respective opposite edges of the side panels. While such blanks may be erected and sealed manually by forming the blank into a rectangular tube, folding in the bottom end panels, applying adhesive and finally folding and sealing the lateral bottom panels, it is economically desirable to perform some or all of these operations automatically in a sealing machine or in an erecting and sealing machine.
A number of erecting and sealing machines are shown in the prior art, e.g. Jones U.S. Pat. No. 3,333,514; Pearson U.S. Pat. No. 3,421,415; Reichert U.S. Pat. No. 3,828,659; Trosdorff U.S. Pat. No. 3,902,407; Reichert U.S. Pat. No. 3,952,636; Reichert U.S. Pat. No. 3,987,710; Reichert U.S. Pat. No. 4,041,850; Reichert U.S. Pat. No. 4,044,657; Mancini U.S. Pat. No. 3,967,434; and Dice, Jr. U.S. Pat. No. 4,018,143. Derderian U.S. Pat. No. 3,948,151 is an example of a sealing machine alone.
Various complex mechanical devices have been employed to perform the required erecting, folding and sealing functions. Jones U.S. Pat. No. 3,333,514, for example, discloses a progressive operation in which the erection is accomplished by levers or star wheels in conjunction with transversely moving squaring fingers. Pearson U.S. Pat. No. 3,421,415 employs a special blank having interconnected flaps at one end and a pair of moving platens for sealing the bottom flaps. Reichert U.S. Pat. No. 3,828,659, also utilizing a blank with interconnected flaps on one end, delivers the blanks in a vertical position and folds the interconnected flaps against the sides to produce an erected box with the top flaps held in the fully opened position.
The following Reichert patents all relate to a single erecting and sealing machine: Reichert U.S. Pat. No. 3,952,632 discloses a dispensing apparatus for such a machine designed to drop blanks vertically into an erecting mechanism. Reichert U.S. Pat. No. 3,987,710 describes a box squaring device in conjunction with a vacuum erecting system. Reichert U.S. Pat. No. 4,041,850 describes a method of erecting cases including steps of positioning the blanks over a drop chute. Reichert U.S. Pat. No. 4,044,657 discloses a method and apparatus for sealing an erected carton using a pair of moving platens.
Mancini U.S. Pat. No. 3,967,434 discloses a carton erecting, filling and closing machine employing an intermittent motion sequence which stops at each station to perform the particular operation required.
Dice Jr. U.S. Pat. No. 4,018,143, like Mancini U.S. Pat. No. 3,967,434, employs an intermittent motion mechanism for a case erecting and sealing machine.